Regarding a method for synthesizing a 1-(2H)-isoquinoline derivative having a substituent at the 3-position, several reports have already been made. For example, in 1968, Rose et al. have reported a method of allowing ammonia to act on a 3-aryl isocoumarin derivative, so as to synthesize a 1-(2H)-isoquinolone derivative (refer to Non-Patent Document 1). In addition, in 1982, Poindexter has reported a method of synthesizing a 1-(2H)-isoquinolone derivative by the reaction of N,2-dimethylbenzamide with a nitrile derivative (refer to Non-Patent Document 2).
Moreover, the pharmacological activity of such an isoquinolone derivative has also been reported. Researchers of Octamer have reported an isoquinolone derivative having anti-inflammatory action (refer to Patent Document 1). Also, researchers of Guilford have reported that 3-phenyl-1-(2H)-isoquinolone has an inhibitory activity on poly(ADP-ribose)polymerase, and that it is used as a radiosensitizer (refer to Patent Document 3). Moreover, with regard to an isoquinolone derivative having anticancer action, in 1989, researchers of Du Pont have reported that a 3-(1-naphthyl)-1-(2H)-isoquinolone derivative exhibits anticancer action (refer to Patent Document 2). Thereafter, Won-Jea Cho et al. have reported a 3-aryl isoquinolone derivative having anticancer action (refer to Non-Patent Documents 3 to 8). However, the anticancer activities of such isoquinolone derivatives have not been necessarily sufficient. Thus, it has been desired that a compound having higher anticancer activity and also having preferred physical properties be developed.    [Patent Document 1] International Publication WO98/51307    [Patent Document 2] U.S. Pat. No. 4,942,163    [Patent Document 3] International Publication WO99/11624    [Non-Patent Document 1] J. Chem. Soc. (C), pp. 2205-2208 (1968)    [Non-Patent Document 2] J. Org. Chem., vol. 47, pp. 3787-3788 (1982)    [Non-Patent Document 3] Arch. Pharm. Res., vol. 20, pp. 264-268 (1997)    [Non-Patent Document 4] Bioorg. Med. Chem. Lett., vol. 8, pp. 41-46 (1998)    [Non-Patent Document 5] Arch. Pharm. Res., vol. 24, pp. 276-280 (2001)    [Non-Patent Document 6] Bioorg. Med. Chem., vol. 10, pp. 2953-2961 (2002)    [Non-Patent Document 7] Tetrahedron Lett., vol. 45, pp. 2763-2766 (2004)    [Non-Patent Document 8] J. Org. Chem., vol. 69, pp. 2768-2772 (2004)